1.11 Drugs and the Peripheral NS

Question 1

How does the PNS breakdown?

Answer 1

PNS to motor and sensory NS
Motor to somatic and autonomic
autonomic to sympathetic and parasympathetic

Question 2

Which NS uses:

1) efferent nn fibres
2) afferent nn fibres

Answer 2

1) Sensory

2) motor`

Question 3

Which break down of motor NS is

1) voluntary
2) involuntary

Answer 3

1) somatic

2) autonomic

Question 4

What happens to the following in

1) sympathetic innervation
2) parasympathetic innervation
a) pupils
b) lens of eye adjusts for ___ vision

Answer 4

1) Pupils dilate (peripheral vision)
b) far
2) Pupils constrict
b) closer

Question 5

What happens to the following in

1) sympathetic innervation
2) parasympathetic innervation
a) HR
b) Blood vessels to limbs
c) to visceral organs
d) brain activity

Answer 5

1) Heart rate increases
Blood vessels to limb muscles dilate
Blood vessels to visceral organs constrict
Brain activity general alertness
2) Heart rate decrease
Blood vessels to limb muscles constrict
Blood vessels to visceral organs more dilated
Brain activity normalise

Question 6

What happens to the following in

1) sympathetic innervation
2) parasympathetic innervation
a) Respiratory rate
b) salivary secretions

Answer 6

1) a) increases
b) reduced
2) a) decreases
b) increased

Question 7

a) What neurotransmittor is used at the following junctions in sympathetic NS
1) preganglionic
2) postganglionic
b) What are the exceptions to this rile

Answer 7

a) 1) ACh (acetyl choline)
2) NA (noradrenaline)
b) sweat glands everything is ACh and , adrenal medulla, ACh causes secretionb of adrenaline into the blood.

Question 8

a) What neurotransmittor is used at the following junctions in parasympathetic NS
1) preganglionic
2) postganglionic
b) At neuromuscular junctions in somatic what neurotransmittor is used

Answer 8

a) 1) ACh
2) ACh
b) ACh!!
(acetyl choline)

Question 9

Describe synthesis of Acetyl choline at junctions:

i.e. enzyme and substrates

Answer 9

choline/choline acetyl transferase (CAT) is the synthetic anexyme, formed from choline and AcCoA

Question 10

Describe storage of Acetyl choline at junctions:

2) WhY?

Answer 10

vesicles

2) prevent degradation

Question 11

Describe release of Acetyl choline at junctions:

Answer 11

exocytosis into synapse

Question 12

Describe receptor interactions of Acetyl choline at junctions:

Answer 12

binds to a muscarinic or a nicotinic receptor

Question 13

Describe termination of Acetyl choline at junctions:

Answer 13

broken down in synapse by acetylcholine esterase (degradation enzyme)

Question 14

The actions of ACh are mediated via 2 main classes of ACh receptor
Names:

Answer 14

Muscarinic receptors

Nicotinic receptors

Question 15

1) What are the subclasses of muscarinic receptor?
2) What type of receptor is it ?
3) Where is the receptor located within the body?
4) response time compared to nicotinic?

Answer 15

1) M1,2,3,
2) G protein coupled
3) Located at postganglionic parasympathetic synapses
(found at target organ/ effector tissue)
4) slow (seconds)

Question 16

Nicotinic receptors (nACh), What are the 2 main receptor subtypes: (excitatory? or inhibitory?)

b) what type of receptor is it?
c) Where is it located?
d) response time compated to muscarinic:

Answer 16

muscle-type: neuromuscular junction (NMJ) (excitatory)

2) neuronal type- brain and autonomic ganglia (excitatory)
b) Ligand gated ion channels (or ionotropic receptor)
c) Located in ganglia and on NMJ ( preganglionic and in muscles(“only” target mm found in))

Question 17

Fill spaces:
• Muscarinic receptors are just located in A.
• Nicotinic neuronal type are involved in B
• Nicotinic muscle type are involved in C

Answer 17

A) parasympathetic system,
B) parasympathetic and sympathetic system.
C) somatic effects.

Question 18

Knowing muscarinic receptors are involved in the parasympathetic system. What effect does a muscarinic A)agonist and B) antagonist have on:

1) pupillary muscle in pupil
2) focal length of lens (ciliary mm)
3) bronchioles

Answer 18

A) 1) increases pupil constriction (contraction)
2) decreases focal length (contracts)
3)Bronchoconstriction
B) the opposite

Question 19

Knowing muscarinic receptors are involved in the parasympathetic system. What effect does a muscarinic A)agonist and B) antagonist have on:
1) cardiac output (=HR*SV(force))
2) GI motility
3) exocrine gland secretion (sweating, salivation, bronchiol secretion)
C) Whats wrong with this?

Answer 19

A)1) decrease
2) increases
3) increases
B) the opposite 
C) sweating is actually a sympathetic effect

Question 20

1) What are muscarinic agonists know as ?
2) Why?
3) What are muscarinic antagonists known as ?

Answer 20

1) as parasympathomimetics
2) they stimulate muscarinic receptors
3) as parasympatholytic .

Question 21

Considering the effects of antagonist muscarinic receptors what are they used for get a few:

Answer 21

pupil dilation in eye surgery , decrease oral /respiratory secretions before oral procedures and as an adjunct to anaesthesia (as when your on ventilator you don’t have cough reflex), resuscitation in bradycardia, asthma patients , GI motility= motion sickness

Question 22

Considering the effects of agonist muscarinic receptors what are they used for get a few:

1) how does it treat glaucoma (build of lfui din the eye)
2) the oral condition it treats
a) how is it taken
b) side effects

Answer 22

1) focus on near vision + also allows increase drainage of aqueous humour
Contraction of sphincter muscle causes pupil constriction
2) xerostomia: stimulates saliva secretions
a) Taken systemically
b) Side effects: muscarinic-sweating, nausea, minimal cardiovascascular side effect (due to low dose)

Question 23

Treatment for :

1) asthma
2) Xerostomia
3) Motion sickness (decrease gastric motility)
4) Bradycardia

Answer 23

muscarinic antagonist: 1,3, 4

muscarinic agonist: 2

Question 24

Treatment for :

1) to decrease secretions
2) pupil dilation in eye surgery
3) glaucoma

Answer 24

muscarinic antagonist: 1,2,

muscarinic agonist: 3

Question 25

What is the effect of nicotinic antagonists?

Answer 25

loss of sympathetic & parasympathetic reflexes, especially cardiac

Question 26

What is the effect of nicotinic agonists targeting nicotinic receptors found at NMJ?

2) What is the importance of this in medicine when agonist is SYNTHETIC:
3) What does it cause?
4) used when?

Answer 26

Stimulation of these receptors by ACh causes depolarisation (in muscle fibre this is known as an end plate potential (EPP)) and contraction of the skeletal muscle fibre

2) Because the synthetic agonist is not metabolised rapidly by acetylcholinesterase, the fibre is persistently depolarised resulting in loss of further electrical excitability-known as depolarising block
3) depolarising block
4) paralysis/ muscle relaxation (for surgery)

Question 27

nicotinic agonists or antagonstic cause :

1) depolarising block
2) non-depolarising block
b) why?
c) What do they both have in common?

Answer 27

1) agonist b)synthetic agonist is not metabolised rapidly by acetylcholinesterase,fibre is persistently depolarised resulting in loss of further electrical excitability-known as depolarising block
2) antagonist b) Hyperpolarisation, inhibition of EPPs (initial depolarisation)
Muscle fibre relaxation
c) both cause paralysis (used in surgery)

Question 28

What is anticholinesterases used to for? (2)

Answer 28

Myasthenia gravis

Induce paralysis for surgery

Question 29

what is used to treat myasthenia gravis?

2) how does it work?
3) What is this disease?

Answer 29

1) anticholinesterases
2) inhibits acetylcholinesterase, thus ACh not metabolised nad action not terminated, amount of ACh isecreted increase therefore can have greater effect. Too much and can be harmful
3) (autoimmune disease, circulating antibodies against muscle nicotinic receptors)